Trapping shape-controlled nanoparticle nucleation and growth stages via continuous-flow chemistry

Abstract

Continuous flow chemistry is used to trap the nucleation and growth stages of platinum-nickel nano-octahedra with second time resolution and high throughputs to probe their properties ex situ. The growth starts from poorly crystalline particles (nucleation) at 5 seconds, to crystalline 1.5 nm particles bounded by the {111}-facets at 7.5 seconds, followed by truncation and further growth to octahedral nanoparticles at 20 seconds.

New insight into the effect of mass transfer on the synthesis of silver and gold nanoparticles

“…A change in the surface chemistry of initially formed NPs over time was observed by other authors as well. 29,54 Polte et al discussed the hydrolysis of sodium borohydride attached to silver NPs after 5-90 min (depending on whether additional stabilizers, apart from sodium borohydride, were present; the synthesis was performed with and without additional stabilizers). The transition of [BH 4 ] − to [BIJOH) 4 ] − was described to result in further aggregation and hence a second growth step yielding an increase in the mean diameter from 2-5 nm to the final NP size of approximately 10 nm.…”

Continuous Synthesis of Nanocrystals via Flow Chemistry Technology

“…The much smaller sized microreactor also enhanced the safety of experiments with toxic and highly reactive chemicals . Microreactors can also be equipped with automated feeding and sampling machines, programmed heating and cooling elements, and online detectors; thus, flow synthesis of nanocrystals have the advantages of implementing high‐throughput screening experiments in evaluating material preparation method, optimizing of synthesis condition, and determining nucleation/growth kinetics …”

Manipulation and Control of Structure and Size of Inorganic Nanomaterials in Microchemical Systems

“…(C) Continuous‐flow microreaction with a shock heating step: (a) schematic of the microreactor. (b) TEM images of Pt‐Ni nanoparticles with different reaction times: 5 s, 7.5 s, 10 s, and 20 s. Reprinted with permission from . Copyright 2017, Royal Society of Chemistry.…”

“…To trap the nucleation and growth of Pt‐Ni nano‐octahedra, LaGrow et al developed a continuous microfluidic platform with a high time resolution on the order of seconds, as demonstrated in Fig. C . The reaction process was controlled by temperature: reaction at 240 °C and quenching at room temperature.…”